To me, Soilwork's best albums are Chainheart Machine, A Predator's Portrait, Natural Born Chaos, and Figure Number Five. That's really where they were the most inspired and kept adding new things to each release. After Natural Born Chaos I wondered where they were going to go next, and Figure Number Five was even more amazing. "Stabbing The Drama" was where things started to get less inspired, but it was still decent.
They put out a long string of some of my favorite metal albums ever, and I think that especially now with Peter Wichers gone they're going to have trouble competing with themselves.
That all being said, their most recent two albums are still very solid, and I think the songs are probably catchier in that the lyrics are simpler, which will win them some new fans in the States I'm sure.